thanks for the info. I remember now that that few actions are in fact 
not exposed outside of the virtual keyboard Behaviour.

The following AppleScript code is unsupported and (although unlikely) 
can stop working in future versions of Remote Buddy, but for the 
moment it'll do what you are looking for:

-- snip -- 
tell application "Remote Buddy"

-- Start pressing Ctrl key 
behaviouraction actionIdentifier "input.keyboardCursor.Ctrl" event 
"pressed"

-- Example: hold Ctrl key for one second 
delay 1

-- Release Ctrl key 
behaviouraction actionIdentifier "input.keyboardCursor.Ctrl" event 
"released"

end tell 
-- snap --

You can rip above sample code apart and package it into two 
AppleScript actors, both part of the same action, one executed on the 
press:

-- snip -- 
tell application "Remote Buddy" to behaviouraction actionIdentifier 
"input.keyboardCursor.Ctrl" event "pressed" 
-- snap --

and one executed on the release of a button:

-- snip -- 
tell application "Remote Buddy" to behaviouraction actionIdentifier 
"input.keyboardCursor.Ctrl" event "released" 
-- snap --

Best regards, 
Felix Schwarz